Filter access to /dev/mem found in arch/arm/Kconfig.debug

Help text

If this option is disabled, you allow userspace (root) access to all
of memory, including kernel and userspace memory. Accidental
access to this is obviously disastrous, but specific access can
be used by people debugging the kernel.

If this option is switched on, the /dev/mem file only allows
userspace access to memory mapped peripherals.

If in doubt, say Y.

Filter access to /dev/mem found in arch/arm64/Kconfig.debug

Help text

If this option is disabled, you allow userspace (root) access to all
of memory, including kernel and userspace memory. Accidental
access to this is obviously disastrous, but specific access can
be used by people debugging the kernel.

If this option is switched on, the /dev/mem file only allows
userspace access to memory mapped peripherals.

If in doubt, say Y.

Filter access to /dev/mem found in arch/powerpc/Kconfig.debug

Help text

This option restricts access to /dev/mem. If this option is
disabled, you allow userspace access to all memory, including
kernel and userspace memory. Accidental memory access is likely
to be disastrous.
Memory access is required for experts who want to debug the kernel.

Filter access to /dev/mem found in arch/s390/Kconfig.debug

Help text

This option restricts access to /dev/mem. If this option is
disabled, you allow userspace access to all memory, including
kernel and userspace memory. Accidental memory access is likely
to be disastrous.
Memory access is required for experts who want to debug the kernel.

Filter access to /dev/mem found in arch/unicore32/Kconfig.debug

Help text

If this option is disabled, you allow userspace (root) access to all
of memory, including kernel and userspace memory. Accidental
access to this is obviously disastrous, but specific access can
be used by people debugging the kernel.

If this option is switched on, the /dev/mem file only allows
userspace access to memory mapped peripherals.

Filter access to /dev/mem found in arch/x86/Kconfig.debug

Help text

If this option is disabled, you allow userspace (root) access to all
of memory, including kernel and userspace memory. Accidental
access to this is obviously disastrous, but specific access can
be used by people debugging the kernel. Note that with PAT support
enabled, even in this case there are restrictions on /dev/mem
use due to the cache aliasing requirements.

If this option is switched on, the /dev/mem file only allows
userspace access to PCI space and the BIOS code and data regions.
This is sufficient for dosemu and X and all common users of
/dev/mem.